URLTest.java Demonstrates try/catch blocks. #Programming Code Examples #Java/J2EE/J2ME #Basic Java

/** Taken from Core Web Programming from 
 *  Prentice Hall and Sun Microsystems Press,
 *  .
 *  © 2001 Marty Hall and Larry Brown;
 *  may be freely used or adapted.  
 */
 
 // Further simplified getURL method. 
 
 public URL getURL() {
    if (url != null) {
      return(url);
    }
    System.out.print("Enter URL: ");
    System.out.flush();
    BufferedReader in = new BufferedReader(
                          new InputStreamReader(System.in));
    String urlString = null;
    try {
      urlString = in.readLine();
      url = new URL(urlString);
    } catch(MalformedURLException mue) {
      System.out.println(urlString + " is not valid.n" +
                        		 "Try again.");
      getURL();
    } catch(IOException ioe) {
      System.out.println("IOError when reading input: " + ioe);
      ioe.printStackTrace(); // Can skip return(null) now
    } finally {
      return(url);
    }
  }

import java.net.*; // For URL, MalformedURLException
import java.io.*;  // For BufferedReader

/** A small class to demonstrate try/catch blocks.
 *
 *  Taken from Core Web Programming from
 *  Prentice Hall and Sun Microsystems Press,
 *  .
 *  © 2001 Marty Hall and Larry Brown;
 *  may be freely used or adapted.
 */

public class URLTest {
  public static void main(String[] args) {
    URLTest test = new URLTest();
    test.getURL();
    test.printURL();
  }

  private URL url = null;

  /** Read a string from user and create a URL from it. If
   *  reading fails, give up and report error. If reading
   *  succeeds but URL is illegal, try again.
   */

  public URL getURL() {
    if (url != null) {
      return(url);
    }
    System.out.print("Enter URL: ");
    System.out.flush();
    BufferedReader in = new BufferedReader(
                          new InputStreamReader(System.in));
    String urlString;
    try {
      urlString = in.readLine();
    } catch(IOException ioe) {
      System.out.println("IOError when reading input: " + ioe);
      ioe.printStackTrace(); // Show stack dump.
      return(null);
    }
    try {
      url = new URL(urlString);
    } catch(MalformedURLException mue) {
      System.out.println(urlString + " is not valid.n" +
                         "Try again.");
      getURL();
    }
    return(url);
  }

  /** Print info on URL. */

  public void printURL() {
    if (url == null) {
      System.out.println("No URL.");
    } else {
      String protocol = url.getProtocol();
      String host = url.getHost();
      int port = url.getPort();
      if (protocol.equals("http") && (port == -1)) {
        port = 80;
      }
      String file = url.getFile();
      System.out.println("Protocol: " + protocol +
                         "nHost: " + host +
                         "nPort: " + port +
                         "nFile: " + file);
    }
  }
}

/** Taken from Core Web Programming from 
 *  Prentice Hall and Sun Microsystems Press,
 *  .
 *  © 2001 Marty Hall and Larry Brown;
 *  may be freely used or adapted.  
 */
 
  // Simplified getURL method.
  
  public URL getURL() {
    if (url != null) {
      return(url);
    }
    System.out.print("Enter URL: ");
    System.out.flush();
    BufferedReader in = new BufferedReader(
                          new InputStreamReader(System.in));
    String urlString = null;
    try {
      urlString = in.readLine();
      url = new URL(urlString);
    } catch(MalformedURLException mue) {
      System.out.println(urlString + " is not valid.n" +
                       			 "Try again.");
      getURL();
    } catch(IOException ioe) {
      System.out.println("IOError when reading input: " + ioe);
      ioe.printStackTrace(); // Show stack dump
      return(null);
    }
    return(url);
  }

Note: Brought from our old site: http://www.salearningschool.com/example_codes/ on Jan 2nd, 2017 From: http://sitestree.com/?p=10218
Categories:Programming Code Examples, Java/J2EE/J2ME, Basic Java
Tags:Java/J2EE/J2MEBasic Java
Post Data:2017-01-02 16:04:23

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